Protective effects of Schisandrin B on cigarette smoke-induced airway injury in mice through Nrf2 pathway

Schisandrin B (SchB), a dibenzocyclooctadiene derivative isolated from Schisandra chinensis, has been reported to have anti-inflammatory effects. However, the protective effects of SchB on cigarette smoke (CS)-induced lung inflammation remain unclear. This study was to investigate the effects of SchB on CS-induced lung inflammation in mice. The mice were exposed to CS to develop lung inflammation. SchB was given 1h before CS exposure daily for five consecutive days. The levels of inflammatory mediators TNF-α, IL-1β, and IL-6 in bronchoalveolar lavage fluid (BALF) were measured in this study. SOD, GSH, MPO and MDA contents were also detected. Furthermore, the expression of Nrf-2 and NF-κB were detected by western blot analysis. Histopathological analyses showed that SchB had protective effects against CS-induced lung inflammation. The levels of inflammatory mediators TNF-α, IL-1β, and IL-6 in BALF were also inhibited by SchB. CS-induced MPO activity and MDA content were inhibited by SchB. The levels of SOD and GSH were up-regulated by SchB. SchB significantly inhibited CS-induced NF-κB activation and up-regulated the expression of Nrf2 and HO-1. In conclusion, these data suggest that SchB protects against CS-induced lung inflammation by activating Nrf2 and inhibiting NF-κB signaling pathway.